In recent years, two-in-one PCs which can be used in the two forms of a notebook personal computer (PC) and a tablet have been sold. The two-in-one PCs include a detachable two-in-one PC system in which a housing including a display is attachable to and detachable from a housing including a keyboard. Main components such as a central processing unit (CPU) are provided in the housing including the display.
In some detachable two-in-one PCs, a housing including a display and a housing including a keyboard are each provided with a battery. When a housing including a display and a housing including a keyboard are each provided with a battery, the two batteries can be used in a switching manner. In general, a large-capacitance capacitor needs to be provided to prevent a decrease in a power supply voltage supplied to information equipment when a battery which supplies power to a PC is switched at the time of a high load.